The invention relates to a module carrier 1 and to a method for producing a module carrier.
Such a module carrier for a door module of a motor vehicle door normally bears multiple functional elements, for example parts of a window regulator for the adjustment of a window pane of the motor vehicle door, at least one loudspeaker or parts of a door-closing system. It is known for a module carrier of said type to be formed substantially by an organic sheet and for at least one seal to be arranged on an encircling outer edge of the module carrier, by means of which seal a sealed connection of the module carrier to a door structure of the motor vehicle door can be realized.
The fact that the module carrier is formed substantially by organic sheet means in this case that the organic sheet forms that part of the module carrier which is subjected to the major part of the forces that act under normal operating conditions. This may be in particular that part of the module carrier on which one or more guide rails of a window regulator are provided. A (coherent) part (which for example bears one or more guide rails) of the module carrier composed of organic sheet, or multiple parts (which for example bear one or more guide rails) of the module carrier composed of organic sheet extend for example over approximately 30% or more of the area of the module carrier. In particular, the organic sheet may extend over more than 40% and generally over at least 50% of the area of the module carrier, such that the organic sheet thus also makes up a corresponding fraction of more than 40% or approximately 50% or more of the surface of the module carrier. To fully utilize the strength advantages of the organic sheet, it is generally sought to maximize the fraction of the area of the module carrier made up by the organic sheet. A multi-part form of the organic sheet on a module carrier is not ruled out here.
A major constituent part of the module carrier is for example a panel-like semifinished part, which is composed of an organic sheet. Thus, the organic sheet defines a substantially areal extent of the module carrier, though may be supplemented by further components or materials. For example, metallic elements and/or plastics elements may be incorporated into the organic sheet or attached to the organic sheet.
The organic sheet involves a thermoplastics material reinforced with endless fibers, wherein endless fibers are embedded in the form of lays, wovens or knits composed of glass fibers, Kevlar fibers, carbon fibers or plastics fibers into a thermoplastic matrix. A suitable thermoplastics material for the matrix is for example polyamide owing to its good adhesion characteristics with respect to the fibers.
The expression “reinforced with endless fibers” is to be understood to mean that the length of the fibers used for the reinforcement is limited substantially by the size of the panel-like organic sheet. Generally, a fiber has no discontinuities within the organic sheet.
Normally, on a module carrier for a door module, there are provided multiple types of interfaces which serve on the one hand for the fixing of the module carrier to a door structure of a motor vehicle door and on the other hand for the connection of the functional elements and/or further components of the motor vehicle door to the module carrier. Such interfaces are defined for example by fastening openings for the fixing of the module carrier to a door structure. Likewise, it is generally the case that multiple fastening openings, screw bosses and/or bearing points and surfaces are formed on the module carrier, which permit an intended connection of functional elements and/or of at least one further component, for example of a door inner lining, to the module carrier. Furthermore, it is normally the case that at least one passage opening for a functional element is formed on the module carrier. It is then for example possible for a component coupled to a functional element or a part of the functional element itself to engage through the module carrier or to extend through the module carrier through a passage opening of said type. For example, a passage opening of said type serves for the leadthrough of an actuating linkage, of a cable or of a (drive) shaft.
In the case of a module carrier which is formed substantially by organic sheet, the formation of defined interfaces and/or passage openings by means of the organic sheet itself is generally possible only within certain limits, because a local deformation of the organic sheet gives rise to tensile forces which, owing to the fibers, propagate relatively extensively through the module carrier. Also, passage openings formed out of the organic sheet itself often cannot be readily produced with the desired precision and with the narrow tolerances that must be adhered to specifically in the automotive sector for industrial mass production.
From DE 10 2010 053 381 A1, it has hitherto merely been known to provide molded-on portions composed of thermoplastics material on an organic sheet. The difficulties that arise in the use of an organic sheet as the main constituent part of a module carrier for a door module of a motor vehicle door are however not discussed in said document.